PLC including I/O points and user storage capacity the capacity of two aspects.
Amount of storage capacity that is required by the user program is not only associated with the functions of the PLC system, but also with the capabilities of the program level. An experienced programmer and a beginner, when completing the same complex functions, the procedure can vary as much as 25%, so beginners should stay when the estimated storage capacity margin.
PLC I/O points, largely reflect the functional requirements of the PLC system, I/O points are determined on the basis of, and according to the following formula to estimate the storage capacity, plus the margin 20%~30%.
Memory (bytes) = switch I/O point number X10 + analog I/O channels x100
In addition, the choice of storage capacity at the same time, pay attention to the types of memory options.
(B) Selection of I/O points
PLC I/O points average prices are still relatively high, so the number of reasonable selection of PLC I/O points, to meet control requirements and strive to use the minimum number of I/O points, but you must have a certain margin.
I/O point numbers are usually based on control of input and output signals of the actual need, coupled with the 10%~15% margin to determine.